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T. D U NGAN. ELECTRIC METER.

NOJ 605,665. Patented June 14, 1898.

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T. DUNCAN. ELECTRIC METER. No. 605,665. r Patented June 14, 1898.

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ELEGTRIG METER.

No. 605,665. Patented June 14,1898;

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T DUNCAN ELECTRIC METER.

Patented .June 14, 1898.

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T. DUNG A N. ELECTRIC METER.

Patented June 14, 18 98.

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wmaoo UNITED STATES" PATENT OFFICE;

' THOMAS DUNCAN, on FORT WAYNE, INDIANA.

ELECTRIC METER.

SPECIFIQQTIQN forming'part of Letters Patent No. 605,665, dated June 14,1898.

Application filed August 6, 1897. Renewed May 18, 1898. Serial No.68l,090. (No model.)

To aZZ whom it may concern Be it known that I,'THoM'As DUNCAN, of FortWayne, in the county of Allen and State of Indiana, have inventedcertain new and useful Improvements in Electric Meters, of which thefollowing is a specification.

This invention relates to alternating-current meters ofthat'classinwhich a rotary armature is set in motion by the inductive action oftwo or more magnetic fields of differing phase; and it relates moreparticularly to that type of such meters in which the rotary armature isof annular or cylindric form and the magnetic fields are set up byinductive agenciespf whichgpart are placed inside of andpart' exteriorto the armature.

The object of this invention is to improve the efficiency andpracticability of meters of this class by increasing'the torque due toany given current without increasing the energy consumed by the meter,and thus to render the action of the instrument more sensitive andaccurate, especially under light loads, where friction and inertiaordinarily offer a serious disturbing influence Such effective increaseof torque, Ihave discovered, will result from an arrangement of theinternal and external fields such as to increase the number of axes orcenters ofpolarization due to said fields. For example,'in afarniliarform of meter having an annular armature, an external series fieldfandan internal field arranged with its axis at an angle to the axis of theseries field (this arrangement being present in several of the metersnow on the market) I'havefound that by providing an additionalfieldarranged on an axis distinct from the axes of the other fields andso 10- cated that the axis of 'one field extends between two of thefields that are set'upon the opposite side of the annular wall of themeter from the firstfield the torque maybe nearly or quite doubledwithout any appreciable increase in the amount of energy consumed by theinstrument and without in any way altering the drag; In one efiectiveconstruction the exterior or series coils of a meter embodying thisimprovement are pro vided as in former constructions, while the coils ofthe interior fields are mounted upon the poles of a cross-shaped corearranged with its axes intersecting the axis of the series coils.

In the forms shown in my pending application, Serial No. 647,303, filedconcurrently herewith, the coils ofthe several poles of said core areall positively energized by connections with the work circuit. Thepresent case isgenerally similar and shows an almost identical structuremechanically, but diifers in having part of its inner coils closedcircuits, which are'inductively energized by the remaining inner coilsthat are connected in the work-circuit.- The principal differenceelectrically due to this arrangement is that the inner fields are nolongerin step with each other, as in the other application referred to,but the current'inl' theclosed .circuit lags behind the current intheconnected inner circuit, while the latter current,owing to the inductiveaction of the magnetic core, lags behind the current in the outer orseries coils. In each case, however, the lag is less than ninetydegrees, so that a different phase results along each axis ofpolarization, and rotation of'thearmature with a largely-increasedtorque is induced in consequence, and, as before stated, the efficiencyand accuracy-of the meter are greatly improved without adding materiallyto the cost of manufacture or maintenance.

In the accompanying drawings, Figure l is a front elevation of a coulombor ampere-hour meter constructed in accordancewith my invention, one ofthe fanbladesbeing broken awayto better show the parts behind it. Fig. 2is a sectional side elevation thereof. Fig. 3 is a top plan section ofthe meter. Fig. lis a perspective view of the inner fields andconnections. Fig. 5 is a diagrammatic View showing the mannerinwhichfthe'fmeter is connected in circuit. "Figs: 6 and? are similarviews showing different methods of adjusting or calibrating the meter.Fig. 8 is a diagrammatic view showing the several axes of polarization.Fig. 9 illustrates a third method of speed adjustment. Fig. 10 shows amethod of connecting the meter in a high-tension circuit. Fig. 11- showsa wattmeter connection. Fig. 12 shows a different form of windingfor thewattmeter connection. V

In said drawings, A designate'sth'e main frame of the meter, and A anupward-extending transverse yoke which supports the registering trainand the upper spindle-bearing.

I3 designates the annular armature, which is herein shown as comprisinga cylindric rim or wall D and a top wall I), through the center of whichthe arlnature-spindle B passes and to which it is rigidly secured. Thespindle B is mounted to rotate freely in the usual manner and in thecoulomb-meter shown is provided with attached fan-blades 13 thatopperate as usual to afford a drag which varies as the square of thespeed. In a wattmeter such as is indicated in Figs. 11 and 12 this dragwould obviously require to be replaced bya magnetic or other dragvarying directly as the speed.

C C designate the series coils, which are made of heavy wire and aredesigned to be connected in series in the work-circuit by means ofbinding-posts a, that are in thisinstance provided on insulating-blocksa at the back of the meterframe. Said coils C are placed close togetheron opposite sides of the spindle I5 and are enough larger than thearmature to allow the latter to rotate freely within them.'llheyareherein shown as fastened to a cross-barA by means of clamps cand screws c. The bar A rests upon the yoke A just above the fan-bladesB and is detachably secured in place by screws a \Vithin the armature l3is provided a magnetic core D, upon the poles of which two sets of coilsD and D are mounted. The coils D are made of comparatively fine wire andin the coulomb-meter shown have their terminals (1 also connected withthe binding-posts a, so that they are in parallel with the coils O. Thecoils lfiare closed circuits and maybe conveniently made of copper loopsor punchings slipped over the ends of the core D. The latter ispreferably made of laminated iron and of cross shape,with its two axes 11 and 2 9 arranged substantially at right angles to each other. Thecoils D are shown as provided 011 the opposite poles of the core alongthe axis 1 1 and the closed circuits I) 011 the opposite poles along theaxis 2 2. Said axes 1 1 and 2 2 are arranged at angles of approximatelyfortyfive degrees with the axis 3 of the coils O. For purposes ofadjustment and calibration, however, it is frequently desirable to varythese angles, and to this end the core is shown as adjustable about avertical axis. The several laminae of the core are in this instancesecured upon the upper end of a tubular standard D which passes downbetween the series coils and rests upon the cross-bar A? Said standardfits over and is capable of oscillation about a fixed centering tube d,which is insertedin the aperture in the crossbar through which thespindle 13 passes and loosely surrounds said spindle. A lever D" isattached to the lower end of the standard D and is provided at its outerends with an areshaped slot through which a clamping-screw d is passed.By adjusting the lever D in various positions within the limits of itsslot the position of the inner core and fields may be varied withreference to the axis of the series field to produce the speedadjustment desired. An additional or substitute means of adjustment isshown in Fig. (3, in which an inductance-coil I, having an adj ustablecore i, is inserted in the circuit of the coils D. In Fig. 7 anadjustable non-inductive resistance R is inserted in the same manner toprovide the necessary adjustment. This construction thus described willobviously produce fields of force along the three axes 1 1, 2 2, and 33, tending to polarize the armature and to set up Foucault or eddycurrents, which will react to produce rotation owing to the phasedisplacement between the fields. The series field will obviously be instep with the workcurrent; but the self-inductance due to the core Dwill cause the current in the inner coil D to lag behind the workcurrent and the current in the closed circuit D", resulting inductivelyfrom the coils 1), will lag still farther behind. The lag will in eachcase, however, be less than ninety degrees, and the induced field alongthe axis 2 2 will therefore be out of step with both the other fields.

I11 Fig. 10 the meter, instead of being connected directly in thework-circuit, is inserted in a derived circuit energized by thetransformer T, the primary of which is in seriesin the work-circuit. InFig. 11 the inner coils D are connected across the line or in shuntbetween the main leads of the work-circuit, so that the instrument willact as a wattmeter for measuring the energy consumed in thework-circuit. A suitable drag, varying directly as the speed, will inthis case be used in place of the fan drag, as hereinbefore stated. Fig.12 shows a somewhat similar arrangement in which the coils D are dividedand connected partly in shunt between the main leads and partly inparallel with the series coils.

It will be understood that while the particular construction and angulararrangement of the parts herein shown have been found to produce thebest results thus far they are susceptible of various changes andrearrangements without departing from the spirit or losing theadvantages of the invention, which is accordingly broadly andspecifically hereinafter claimed.

I claim as my invention 1. An electric meter provided with an annulararmature and a plurality of magnetic fields part of which are set upwithin and part without the armature, one field being on an axisextending between two other fields that are set up on separate axes onthe opposite side of the annular wall of thearmature from the firstfield, circuit connections energizing part of the fields with currentsof differing phase, and means for inductively energizing the other part.

2. An electric meter provided with an annular armature and a pluralityof coils part of which are located within and part without the armature,one coil being arranged on an axis extending between two other coilsthat are arranged on separate axes on the other side of the annular.wall of the armature from the first coil, circuit connections forenergizing two of the coils by currents of diifering phase, and meansfor inductively energizing the third coil.

3. An electric meter provided with an annular armature, a magnetic fieldset up exterior to the armature, upon an axis extending between twofields set up within the armature upon separate axes, circuitconnections for energizing the outer and one inner field by currents ofdiffering phase, and means for inductively energizing the third field bya current of still difierent phase. v

4. An electric meter provided with an annular armature, coils exteriorto the armature, coils within the armature, circuit con nections forenergizing said outer and inner coils, a magnetic core having part ofits poles inclosed by said inner coils, and closed circuits on the otherpoles of said core.

5. An electric meter provided with an annular armature, coils exteriorto the armature, coils within the armature, circuit connections forenergizing said outer and inner coils by currents of differing phase,closed circuits within the armature apart from the first inner coil, andmeans for inductively energizing said closed circuits.

6. An electric meter provided with an annular armature, coils exteriorto the armature connected in circuit, a cross-shaped mag- 7. An electricmeter provided with an annular armature, coils exterior to the armature,arranged upon an axis intersecting the latter and connected in circuit,a cross-shaped magnetic core arranged with its axes at an angle to theaxis of the outer coils, coils on two poles of'the core, also connectedin circuit, and closed circuits on the other poles of the core.

8. An electric meter provided with an annular armature, coils exterior.to the armature arranged upon an axis intersecting the latter andconnected in circuit, a cross-shaped magnetic core within the armaturearranged with its axes at an angle to the. axis of the outer coils,coils on two poles of the core also connected in circuit, closedcircuits on the other poles of the core, and means for adj usting theangular arrangement of the core with respect to the axis of the outercoils;

' 9. An electric meter provided with an annular armature, a series fieldexterior to the armature, a magnetic core within the armature made ofcross shape with its axes intersecting each other and the axis of theseries field at the center of the armature, coils on two opposite polesof the core connected in circuit, and closed circuits on the other twoTHOMAS DUNCAN.

August, A D. 1897.

Witnesses:

HENRY W. CARTER.- E. M. HULsE.

